用TEAOH-C_4H_9NO复合模板剂合成SAPO-34分子筛的研究 Ⅱ.SAPO-34分子筛的表面酸性和催化性能

Study on Synthesis of SAPO-34 Molecular Sieve Using Composite Template TEAOH-Morpholine Ⅱ. Surface Acidity and Catalytic Performance of SAPO-34 Molecular Sieve

以吗啉 (C4H9NO)为主要模板剂 ,以少量四乙基氢氧化铵 (TEAOH)为辅助模板剂合成了SAPO 34分子筛 ,并用氨吸附红外、核磁共振和氮吸附等手段对合成的SAPO 34分子筛进行了表征 .结果表明 ,与单独以吗啉为模板剂合成的样品相比 ,用复合模板剂合成的分子筛样品的比表面积和孔体积均有所增大 ;由于在分子筛骨架中形成了“硅岛” ,使其B酸量有所增加 ,对甲醇制低碳烯烃反应的催化性能有所改善 .

A composite template tetraethylammonium hydroxide (TEAOH)-morpholine (C 4H 9NO) was used to synthesize SAPO-34 molecular sieve. The SAPO-34 molecular sieve samples were characterized by NH 3-IR, NMR and N 2 adsorption. The characterization results showed that the SAPO-34 molecular sieve sample had larger specific surface area and larger pore volume than those of the molecular sieve sample synthesized with single morpholine as template. Owing to the 'silicon island' structure formed, more Brnsted acid sites came into being in the SAPO-34 sample synthesized with TEAOH-C 4H 9NO, which had better catalytic performance for methanol-to-olefin reaction than the SAPO-34 sample synthesized with morpholine alone.